1. Field of the Invention
The present invention relates to a camera shake correction device, a camera shake correction method, and an imaging device, such as a digital video camera or digital still camera, provided with the camera shake correction device.
2. Description of Related Art
A camera shake correction technique is for reducing camera shake caused during photographic operation, and has been actively studied in recent years. In the camera shake correction technique, it is important to discriminate between camera shake and deliberate camera movement caused by a photographer (camera operator). Such deliberate camera movement is caused by movements of hands performing a camera operation, such as pan and tilt operations. Although a standard imaging device is provided with a function for discriminating between camera shake and deliberate camera movement, it is difficult in general to perfectly discriminate therebetween.
If the imaging device provided with a display unit erroneously identifies deliberate camera movement as camera shake, a displayed image may become unnatural. For example, suppose that a photographer moves the imaging device to the left direction for changing picture composition, and the imaging device determines the movement as camera shake. In this case, shake of a displayed image that should be caused by the camera operation is cancelled, resulting in an unnatural displayed image. Specifically, the displayed image responds to the camera operation with a time lag.
In an imaging device, motion detection is performed according to image information, and camera shake correction is executed based on the motion detection result. If any movement different from camera shake is present within the image, reliability of the motion detection is decreased. Consequently, optimal camera shake correction becomes impossible. This is because the imaging device performs camera shake correction upon identifying any movement of a photographic subject different from camera shake as a component of camera shake.
It is urgent that problems of camera shake correction, such as one described above, should be solved. Specifically, the kind of problems to be solved derives from failure in discrimination between camera shake and deliberate camera movement, or from the presence of any movement different from camera shake.